Kangaroo2 Physics Engine Basis

I apologize if this question is too broad, but I'm trying to understand the basis of Kangaroo2, and I've seen it discussed in this post, but no updates in a while. I'm particularly interested in the structural modeling of gridshells, which I have done with dynamic relaxation (only 3DOF axisymmetric beams though), but would like to use a more stable solver.

While I've looked through the open source code for ShapeUp/ShapeOp as referenced in the above post, I'm not a C++ user (mainly python and C#). I've tried to implement some constraints in C++, but I think I'm missing something key about the weighting scheme in C++ compared to K2 in order for the axial strains to correctly balance the bending strains, so any enlightenment on the subject would be much appreciated!